U.S. patent number 11,389,975 [Application Number 16/674,872] was granted by the patent office on 2022-07-19 for spring balancer apparatus and method for disassembling the same.
This patent grant is currently assigned to FANUC CORPORATION. The grantee listed for this patent is FANUC CORPORATION. Invention is credited to Ryuji Takikawa.
United States Patent |
11,389,975 |
Takikawa |
July 19, 2022 |
Spring balancer apparatus and method for disassembling the same
Abstract
In a spring balancer apparatus, a flange includes a through-hole
and a first and second flange member, the first flange member
positioned radially inside a compression spring and removably held
on another end of the shaft by a first nut member fastened to a
first external thread on the shaft, the second flange member
including a central hole and removably fixed to an outer periphery
of the first flange member from a rear end plate side. The rear end
plate of a casing includes an abutting part on which an outer
periphery of the second flange member abuts, and an opening through
which a surface of the second flange member is externally exposed
at a position radially inside the abutting part and radially
outside the central hole. At least one of a front end plate and the
rear end plate is removably fixed to a cylindrical body of the
casing.
Inventors: |
Takikawa; Ryuji (Yamanashi,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
FANUC CORPORATION |
Yamanashi |
N/A |
JP |
|
|
Assignee: |
FANUC CORPORATION (Yamanashi,
JP)
|
Family
ID: |
1000006441288 |
Appl.
No.: |
16/674,872 |
Filed: |
November 5, 2019 |
Prior Publication Data
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|
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Document
Identifier |
Publication Date |
|
US 20200147815 A1 |
May 14, 2020 |
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Foreign Application Priority Data
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Nov 14, 2018 [JP] |
|
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JP2018-213988 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B25J
19/0016 (20130101); F16F 15/00 (20130101); F16F
2230/0011 (20130101) |
Current International
Class: |
B25J
19/00 (20060101); F16F 15/00 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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10007251 |
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Aug 2001 |
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DE |
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102010005103 |
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Jul 2011 |
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DE |
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0947296 |
|
Oct 1999 |
|
EP |
|
1419857 |
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May 2004 |
|
EP |
|
H02110488 |
|
Sep 1990 |
|
JP |
|
H05200690 |
|
Aug 1993 |
|
JP |
|
H11-216697 |
|
Aug 1999 |
|
JP |
|
H11277479 |
|
Oct 1999 |
|
JP |
|
2001-225293 |
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Aug 2001 |
|
JP |
|
2002283274 |
|
Oct 2002 |
|
JP |
|
3141978 |
|
Jun 2001 |
|
WO |
|
Other References
Japanese Office Action dated Oct. 27, 2020, in connection with
corresponding JP Application No. 2018-213988 (5 pp., including
machine-generated English translation). cited by applicant .
Japanese Search Report dated Oct. 21, 2020, in connection with
corresponding JP Application No. 2018-213988 (12 pp., including
machine-generated English translation). cited by applicant .
Office Action dated Apr. 22, 2022, in connection with corresponding
German Application No. 102019130064.9 (14 pp., including
machine-generated English translation). cited by applicant.
|
Primary Examiner: Cook; Jake
Attorney, Agent or Firm: Maier & Maier, PLLC
Claims
The invention claimed is:
1. A spring balancer apparatus comprising: a casing including a
cylindrical body, a front end plate, and a rear end plate, the
front end plate and the rear end plate being positioned to close
respective ends of the cylindrical body; a shaft positioned to pass
through the front end plate in a plate thickness direction so as to
be movable in a longitudinal direction; an attachment block fixed
to one end of the shaft, the one end of the shaft being positioned
outside the casing; a flange fixed to another end of the shaft, the
another end of the shaft being positioned inside the casing; and a
compression spring positioned in a compressed state between the
front end plate and the flange, wherein the another end of the
shaft is provided with a first external thread, the flange includes
a through-hole allowing for passage of the shaft, and further
includes a first flange member and a second flange member, the
first flange member being positioned radially inside the
compression spring, the first flange member being removably held on
the another end of the shaft by a first nut member fastened to the
first external thread, the second flange member including a central
hole allowing for passage of the first nut member, the second
flange member being removably fixed to an outer periphery of the
first flange member from the rear end plate side by a fastening
tool, the rear end plate includes an abutting part on which an
outer periphery of the second flange member abuts, and an opening
through which a surface of the second flange member is externally
exposed at a position radially inside the abutting part and
radially outside the central hole, and at least one of the front
end plate and the rear end plate is removably fixed to the
cylindrical body.
2. The spring balancer apparatus according to claim 1, wherein the
rear end plate includes a lid configured to removably close the
opening from outside.
3. A method for disassembling the spring balancer apparatus
according to claim 1, the method comprising: removing the first nut
member and the fastening tool in a state in which the second flange
member is abutted against the abutting part; fastening the first
external thread to the internal thread to push the attachment block
against an outer surface of the front end plate in a state in which
a front end face of a cylindrical jig is abutted against a surface
of the first flange member, the cylindrical jig including an inner
hole provided with an internal thread for fastening of the first
external thread thereto, the cylindrical jig including an outer
surface smaller in outer diameter than a diameter of the central
hole and provided with a second external thread engaged with a
second nut member, and, in this state: fastening the second nut
member relative to the second external thread until the second nut
member abuts on the surface of the second flange member; separating
the front end plate or the rear end plate from the cylindrical
body; and loosening the second nut member.
4. The method for disassembling the spring balancer apparatus
according to claim 3, wherein the first external thread and the
second external thread are reverse-threaded relative to each other.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based on Japanese Patent Application No.
2018-213988, the content of which is incorporated herein by
reference.
FIELD
The present invention relates to a spring balancer apparatus and a
method for disassembling the spring balancer apparatus.
BACKGROUND
A known spring balancer apparatus used for assisting power of an
industrial robot has a compression spring inside thereof, which is
initially loaded with a compression force before the spring
balancer apparatus is mounted on the industrial robot (e.g., see
Japanese Unexamined Patent Application, Publication No. 11-277479).
In disassembling such a spring balancer apparatus for disposal or
other purposes, a press machine or the like has been used to
relieve the compression force of the compression spring.
SUMMARY
An aspect of the present invention is directed to a spring balancer
apparatus including: a casing including a cylindrical body, a front
end plate, and a rear end plate, the front end plate and the rear
end plate being positioned to close respective ends of the
cylindrical body; a shaft positioned to pass through the front end
plate in a plate thickness direction so as to be movable in a
longitudinal direction; an attachment block fixed to one end of the
shaft, the one end of the shaft being positioned outside the
casing; a flange fixed to another end of the shaft, the another end
of the shaft being positioned inside the casing; and a compression
spring positioned in a compressed state between the front end plate
and the flange, wherein the another end of the shaft is provided
with a first external thread, the flange includes a through-hole
allowing for passage of the shaft, and further includes a first
flange member and a second flange member, the first flange member
being positioned radially inside the compression spring, the first
flange member being removably held on the another end of the shaft
by a first nut member fastened to the first external thread, the
second flange member including a central hole allowing for passage
of the first nut member, the second flange member being removably
fixed to an outer periphery of the first flange member from the
rear end plate side by a fastening tool, the rear end plate
includes an abutting part on which an outer periphery of the second
flange member abuts, and an opening through which a surface of the
second flange member is externally exposed at a position radially
inside the abutting part and radially outside the central hole, and
at least one of the front end plate and the rear end plate is
removably fixed to the cylindrical body.
Another aspect of the present invention is directed to a method for
disassembling the spring balancer apparatus having any one of the
above aspects, the method including: removing the first nut member
and the fastening tool in a state in which the second flange member
is abutted against the abutting part; fastening the first external
thread to the internal thread to push the attachment block against
an outer surface of the front end plate in a state in which a front
end face of a cylindrical jig is abutted against a surface of the
first flange member, the cylindrical jig including an inner hole
provided with an internal thread for fastening of the first
external thread thereto, the cylindrical jig including an outer
surface smaller in outer diameter than a diameter of the central
hole and provided with a second external thread engaged with a
second nut member, and in this state; fastening the second nut
member relative to the second external thread until the second nut
member abuts on the surface of the second flange member; separating
the front end plate or the rear end plate from the cylindrical
body; and loosening the second nut member.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a partial view of an exemplary robot with a spring
balancer apparatus mounted thereon according to an embodiment of
the present invention.
FIG. 2 is a longitudinal sectional view showing an initial state of
the spring balancer apparatus of FIG. 1.
FIG. 3 is a longitudinal sectional view showing the state where a
lid is removed from the spring balancer apparatus of FIG. 2.
FIG. 4 is a longitudinal sectional view showing the state where
bolts for fastening a first flange member to a second flange member
and a first nut member fastened to an external thread on a shaft
are removed from the spring balancer apparatus of FIG. 3.
FIG. 5 is a longitudinal sectional view showing the state where a
jig is attached using the external thread on the shaft of the
spring balancer apparatus of FIG. 4.
FIG. 6 is a longitudinal sectional view explaining an operation to
fasten a second nut member of the jig attached to the spring
balancer apparatus of FIG. 5.
FIG. 7 is a longitudinal sectional view showing the state where a
casing body is removed from a front end plate by removing the bolts
of the spring balancer apparatus of FIG. 6.
FIG. 8 is a longitudinal sectional view explaining an operation to
relieve a compression force of a compression spring by loosening
the second nut member of the jig attached to the spring balancer
apparatus of FIG. 7.
FIG. 9 is a flowchart explaining a method for disassembling the
spring balancer apparatus of FIG. 1.
FIG. 10 is a longitudinal sectional view showing a first
modification of the spring balancer apparatus of FIG. 1.
FIG. 11 is a longitudinal sectional view showing a second
modification of the spring balancer apparatus of FIG. 7.
FIG. 12 is a longitudinal sectional view showing a third
modification of the spring balancer apparatus of FIG. 7.
DETAILED DESCRIPTION
Below a description will be given of a spring balancer apparatus 1
and a method for disassembling the spring balancer apparatus 1
according to one embodiment of the present invention with reference
to the drawings.
For example, the spring balancer apparatus 1 according to the
present embodiment is used for assisting power of a motor (not
shown) to drive an arm 120 that is supported so as to be rotatable
relative to a base 110 of an upright articulated robot 100 about a
gravitational axis of the robot 100, namely a horizontal axis, as
shown in FIG. 1.
As shown in FIG. 1, the spring balancer apparatus 1 includes a
casing 2 swingably supported by the base 110, and a shaft 3
swingably attached to the arm 120.
As shown in FIG. 2, the casing 2 includes a cylindrical casing body
(cylindrical body) 4, a front end plate 5 and a rear end plate 6
closing respective ends of the casing body 4, and a sliding bearing
8 disposed inside a through-hole 7 in the front end plate 5 to
support the shaft 3 so that the shaft 3 can move in a longitudinal
direction.
The front end plate 5 is removably attached to the casing body 4
with bolts 9.
The rear end plate 6 is provided integrally with the casing body 4
and includes a peripheral part 10 protruding like an inner flange
at a rear end of the casing body 4 and having a central opening 11,
and a lid 13 removably attached to the peripheral part 10 with
bolts 12 to close the opening 11. The peripheral part 10 serves as
an abutting part on which an outer periphery of a second flange
member 20 (described later) abuts.
An attachment block 14 is attached to one end of the shaft 3
outside the casing 2, and the other end of the shaft 3 inside the
casing 2 is provided with an external thread (the first external
thread) 15.
As shown in FIGS. 3 and 4, the spring balancer apparatus according
to the present embodiment includes a flange 17 attached to and held
by the other end of the shaft 3 with a nut member (the first nut
member) 16 fastened to the external thread 15, and a compression
spring 18 placed in a compressed state between the flange 17 and
the front end plate 5.
The flange 17 includes a disk-like first flange member 19 having a
diameter sized to fit radially inside the compression spring 18,
and a second flange member 20 placed on an outer periphery of the
first flange member 19 in a plate thickness direction and then
removably attached to the first flange member 19 with bolts
(fastening tool) 21 from the rear end plate 6 side.
The first flange member 19 includes at its center a through-hole 22
allowing for passage of the shaft 3. With the other end of the
shaft 3 passing through the through-hole 22, the nut member 16 is
fastened to the external thread 15 on the shaft 3 from the rear end
plate 6 side. This holds the first flange member 19 in place so
that it does not fall off the other end of the shaft 3.
The second flange member 20 includes a central hole 23 having a
lager inner diameter than an outer shape of the nut member 16. The
compression spring 18 is a coil spring having a diameter sized to
fit between the front end plate 5 and the second flange member
20.
A description will now be given of a jig 200 for disassembling the
spring balancer apparatus 1 according to the present
embodiment.
As shown in FIG. 5, the jig 200 includes a jig body 210 and a nut
member (the second nut member) 220. The jig body 210 is formed in a
columnar (cylindrical) shape and includes a central hole 211
axially running from a distal end of the jig body 210 to an
intermediate axial position therein, and an internal thread 212 on
an inner surface of the central hole 211 for fastening thereto of
the external thread 15 on the shaft 3.
The depth of the central hole 211 is set such that the distal end
of the jig body 210 abuts on a surface of the first flange member
19 as the external thread 15 on the shaft 3 positioned with its
attachment block 14 abutting on the front end plate 5 is getting
fastened to the internal thread 212 on the central hole 211.
The jig body 210 further includes an external thread (the second
external thread) 213 on its outer surface near the central hole 211
side distal end. The nut member 220 is fastened to the external
thread 213. In the present embodiment, the external thread 213 and
the internal thread 212 on the jig body 210 are reverse-threaded
relative to each other.
The jig body 210 further includes, near its rear end, a pair of
flat portions 214 for engagement of tools such as s spanner. The
flat portions 214 radially face each other.
Referring to the flowchart of FIG. 9, below a description will be
given of a method for disassembling the above configured spring
balancer apparatus 1 according to the present embodiment.
The disassembling method according to the present embodiment
relates to disassembling the spring balancer apparatus 1 after it
is removed from the robot 100, as shown in FIG. 2.
The state shown in FIG. 2 is a preload state where the compression
spring 18 in the casing 2 is extended by its resilient force so as
to push the second flange member 20 against the abutting part,
namely the peripheral part 10 of the rear end plate 6. This means
that the compression force of the compression spring 18 is received
by the front end plate 5 and the rear end plate 6 of the casing 2,
which makes it difficult to remove the bolts 9 fixing the front end
plate 5 to the casing body 4.
The disassembling method according to the present embodiment begins
with removing the lid 13 of the rear end plate 6 from the rear end
plate 6 by loosening the bolts 12 to uncover the opening 11, as
shown in FIG. 3 (step S1).
Then, as shown in FIG. 4, the nut member 16 exposed to the
uncovered opening 11 is loosened from the external thread 15 on the
shaft 3 and thus removed, and also the bolts 21 fixing the second
flange member 20 to the first flange member 19 are loosened and
removed (step S2).
Then, as shown in FIG. 5, the shaft 3 is moved in the longitudinal
direction to make the attachment block 14 abut on the front end
plate 5, and the external thread 15 on the shaft 3 is fastened to
the internal thread 212 on the central hole 211 of the jig body 210
inserted from the opening 11 of the rear end plate 6.
This positions the jig 200 at a position where the distal end of
the jig body 210 is in tight contact with the surface of the first
flange member 19, as shown in FIG. 6 (step S3).
In this state, the nut member 220 fastened to the external thread
213 on the outer surface of the jig body 210 is rotated relative to
the external thread 213 as indicated by an arrow in FIG. 6 and
moved to a position where the nut member 220 abuts on the surface
of the second flange member 20 (step S4). On completion of step S4,
the attachment block 14 and the nut member 220 of the jig 200 fixed
to the respective ends of the shaft 3 can prevent widening of space
between the front end plate 5 and the second flange member 20.
This means that the compression force of the compression spring 18
that has been received by the front end plate 5 and the rear end
plate 6 of the casing 2 is now taken over by the attachment block
14 and the nut member 220 of the jig 200 coupled by the shaft
3.
Thus, even when the bolts 9 fixing the front end plate 5 to the
casing body 4 are removed, the compression force of the compression
spring 18 remains unrelieved. This allows to remove the casing body
4 from the front end plate 5 by removing the bolts 9, as shown in
FIG. 7 (step S5).
Then, the nut member 220 is rotated relative to the external thread
213 on the jig body 210 as indicated by an arrow in FIG. 8 to be
moved gradually back toward the rear end side of the jig body 210
(step S6).
Once the nut member 220 is moved back to a position where the
compression force of the compression spring 18 is completely
relieved, the spring balancer apparatus 1 can be disassembled.
Thus, advantageously, the spring balancer apparatus 1 and the
method for disassembling the spring balancer apparatus 1 according
to the present embodiment allow for easy disassembly with the
simple jig 200 without having to use a press machine.
In other words, advantageously, this allows for easy disassembly
and disposal of the spring balancer apparatus 1 and easy
maintenance thereof, such as replacement of its components
including the casing 2 and the compression spring 18, on the site
where a press machine is unavailable.
Further, in the present embodiment, the opening 11 in the rear end
plate 6 is closed by the lid 13. This can seal the casing 2 and
prevent entry of dust and mist. Also, the lid 13 is removed at the
time of disassembly, which enables an easy disassembly work.
In the present embodiment, the internal thread 212 and the external
thread 213 on the jig body 210 are reverse-threaded relative to
each other. Advantageously, this reliably prevents loosening
between the internal thread 212 on the jig body 210 and the
external thread 15 on the shaft 3 even when the jig body 210
rotates by friction between the nut member 220 and the jig body 210
during an operation to relieve the compression force of the
compression spring 18 by rotating the nut member 220 as shown in
FIG. 8.
In the present embodiment, the spring balancer apparatus 1 contains
a single compression spring 18 inside the casing 2, but this is by
way of example only; as shown in FIG. 10, the present invention is
applicable to the spring balancer apparatus 1 containing multiple
compression springs 18, 24.
In the present embodiment, the casing body 4 and the rear end plate
6 are integrally formed and the casing body 4 and the front end
plate 5 are separably fixed with the bolts 9, but this is by way of
example only; instead of this, the casing body 4 and the front end
plate 5 may be integrally formed and the casing body 4 and the rear
end plate 6 may be separably fixed with the bolts 25, as shown in
FIG. 11. Still alternatively, both of the front end plate 5 and the
rear end plate 6 may be separably fixed to the casing body 4 with
the bolts 9, 25, as shown in FIG. 12.
Although the above external thread 213 and internal thread 212 on
the jig 200 are reverse-threaded relative to each other, they may
be threaded in the same direction. In that case, the flat portions
214 may be held with a tool to prevent rotation.
As a result, the above-described embodiment leads to the following
aspects.
An aspect of the present invention is directed to a spring balancer
apparatus including: a casing including a cylindrical body, a front
end plate, and a rear end plate, the front end plate and the rear
end plate being positioned to close respective ends of the
cylindrical body; a shaft positioned to pass through the front end
plate in a plate thickness direction so as to be movable in a
longitudinal direction; an attachment block fixed to one end of the
shaft, the one end of the shaft being positioned outside the
casing; a flange fixed to another end of the shaft, the another end
of the shaft being positioned inside the casing; and a compression
spring positioned in a compressed state between the front end plate
and the flange, wherein the another end of the shaft is provided
with a first external thread, the flange includes a through-hole
allowing for passage of the shaft, and further includes a first
flange member and a second flange member, the first flange member
being positioned radially inside the compression spring, the first
flange member being removably held on the another end of the shaft
by a first nut member fastened to the first external thread, the
second flange member including a central hole allowing for passage
of the first nut member, the second flange member being removably
fixed to an outer periphery of the first flange member from the
rear end plate side by a fastening tool, the rear end plate
includes an abutting part on which an outer periphery of the second
flange member abuts, and an opening through which a surface of the
second flange member is externally exposed at a position radially
inside the abutting part and radially outside the central hole, and
at least one of the front end plate and the rear end plate is
removably fixed to the cylindrical body.
According to the above aspect, the cylindrical body and the
attachment block fixed to one end of the shaft are attached to a
robot so as to be rotatable about an axis parallel to a rotational
axis of the robot. When, along with operation of the robot, the
shaft is moved in a direction in which the shaft is pulled out of
the casing, the compression spring is further compressed between
the flange and the front end plate, which generates a resilient
force acting in a direction in which the shaft is pulled into the
casing. This assists power of the robot.
The spring balancer apparatus according to the present embodiment
is disassembled as follows: in the state where the spring balancer
apparatus is removed from the robot, namely where the compression
spring is maximally extended in the casing such that the outer
periphery of the second flange member abuts on the abutting part of
the rear end plate, the first nut member is removed from the first
external thread on the another end of the shaft through the opening
in the rear end plate. Also, the fastening tool securing the second
flange member to the first flange member is removed through the
opening.
Then, a cylindrical jig that includes an inner hole provided with
an internal thread for fastening of the first external thread on
the shaft thereto and an outer surface smaller in outer diameter
than a diameter of the central hole of the second flange member and
provided with a second external thread engaged with a second nut
member is inserted from the opening into the casing, and the first
external thread is fastened to the internal thread. The attachment
block is thereby made to abut on the front end plate, so that the
second nut member of the jig abuts on the second flange member.
This causes the compression force of the compression spring is held
by the attachment block and the second nut member coupled by the
shaft, and thus at least one of the front end plate and the rear
end plate is removed from the cylindrical body. In this state, the
second nut member is loosened from the second external thread on
the jig to gradually widen the space between the front end plate
and the second flange member. This allows to gradually relieve the
compression force of the compression spring. In other words, the
above aspect allows to disassemble the spring balancer apparatus
with a simple jig without having to use a press machine.
In the above aspect, the rear end plate may include a lid
configured to removably close the opening from outside.
With this configuration, the lid is attached to the rear end plate
to close the opening and thus seal the casing, which can prevent
entry of dust and mist. The lid is removed at the time of
disassembly, which enables an easy disassembly work.
Another aspect of the present invention is directed to a method for
disassembling the spring balancer apparatus having any one of the
above aspects, the method including: removing the first nut member
and the fastening tool in a state in which the second flange member
is abutted against the abutting part; fastening the first external
thread to the internal thread to push the attachment block against
an outer surface of the front end plate in a state in which a front
end face of a cylindrical jig is abutted against a surface of the
first flange member, the cylindrical jig including an inner hole
provided with an internal thread for fastening of the first
external thread thereto, the cylindrical jig including an outer
surface smaller in outer diameter than a diameter of the central
hole and provided with a second external thread engaged with a
second nut member, and in this state; fastening the second nut
member relative to the second external thread until the second nut
member abuts on the surface of the second flange member; separating
the front end plate or the rear end plate from the cylindrical
body; and loosening the second nut member.
In the above aspect, preferably, the second external thread and the
internal thread are reverse-threaded relative to each other.
This configuration reliably prevents loosening between the first
external thread on the shaft and the internal thread on the jig
even when the jig attached to the shaft is made to rotate as a
whole by torque applied to the second nut member to rotate and
loosen the second nut member from the second external thread.
The present invention allows to disassemble the spring balancer
apparatus with a simple jig without having to use a press
machine.
* * * * *